MMAFighting.com was the first to report the cancellation, which has since been confirmed by multiple outlets. Borg’s illness was unrelated to his weight cut, according to the report. As a result, the women’s bantamweight championship clash between Amanda Nunes and Valentina Shevchenko has been elevated to the main event.

UFC 215 takes place at Rogers Place in Edmonton, Alberta, Canada on Saturday night and airs on pay-per-view. The card will move forward with 11 bouts. The Las Vegas-based promotion is reportedly looking to rebook Johnson vs. Borg as soon as possible, but a date has not been finalized for the 125-pound title bout.

Johnson has defended the flyweight belt 10 times, tying him with Anderson Silva for most in promotion history. A victory over Borg would have given “Mighty Mouse” sole possession of the all-time record for most title defenses. Johnson had campaigned to fight Borg after the UFC initially wanted to book T.J. Dillashaw as the champion’s next opponent.

The 24-year-old Borg has won five of his last six Octagon appearances, including a unanimous verdict against Jussier da Silva at UFC Fight Night 106 on March 11.